How is African swine fever transmitted and diagnosed?

Dr. Liz Wagstrom, chief veterinarian with the National Pork Producers Council based Des Moines, Iowa, USA, explains how the movement of African swine fever (ASF) is occurring across different parts of the world.

Dr Liz Wagstrom, chief veterinarian with the National Pork Producers Council based Des Moines, Iowa, USA, speaks to The Pig Site's Sarah Mikesell.

"African swine fever is transmitted through close contact. So unlike some of the diseases that we know that are aerosol and move great distances, this is close contact, nose-to-nose; bodily secretions can transmit it. But another concerning transmission factor is the fact that it can be transmitted through meat," said Dr Wagstrom. "It can survive for long times in uncooked or even cured meats. We have reports that it's survived in serrano hams for over a year."

Diagnosing African Swine Fever

Also concerning is how to diagnose a sick animal because the symptoms of ASF can mimic other diseases.

"Whether it's Salmonella septicemia or some of the things we'd see fairly regularly, it's really important to have your veterinarian on board and make sure that they're sending in the correct diagnostic samples," she noted.

In the US, if there's a case that is suspected it could be African swine fever, state or federal veterinary authorities should be notified to do a foreign animal disease investigation. This ensures samples are being sent to reputable laboratories who are using validated tests, and that veterinarians are sending in the samples of choice, which are spleen, tonsils and whole blood.

Global Diagnostic Use

"Europe has had a lot of experience with doing a great amount of surveillance. So they're testing wild boar, and they're using PCRs," Dr Wagstrom said.

They are also looking at antibodies as well as the antigen that you'd detect with a PCR. Having robust surveillance, including a lot of tests and testing capacity, and being comfortable running those tests is going to be really valuable as you look at controlling an outbreak situation.

"It's also really critical to have a test that you're comfortable that a positive is truly is positive, and that a negative truly is negative," she explained. "That's really important when you're talking about a disease that has the trade impacts, as well as the animal health impacts that African swine fever has."